The Harris County Republican Party released a flyer Monday attacking Houston mayoral candidate Ben Hall for his Democratic ties and previous support for a nondiscrimination ordinance.

Among top-tier mayoral candidates, Hall, a Democrat, is the most ardent critic of the city's equal rights ordinance, known as HERO. The law is set to appear on November's ballot.

"Ben Hall says yes to HERO ordinance in 2013," the GOP flyer reads, citing a 2013 Harris County Democratic Party questionnaire on which Hall said he would support a nondiscrimination ordinance.

The ad also labels Hall a "current Democratic Party sustaining member" and claims he contributed more than $100,000 to Democrats, including President Barack Obama, Democratic presidential candidate Hillary Clinton and Secretary of State John Kerry, citing campaign finance reports.

Hall responded in a statement Tuesday afternoon saying he has been "crystal clear" on HERO.

"Ben Hall is the only candidate, Democrat or Republican, who has been opposed to the HERO ordinance from the very beginning, long before the campaign began for Houston Mayor, long before the court put it on the November ballot," he said.

Hall has been backed by several pastors' groups and conservative power broker Steven Hotze, who publishes an influential endorsement mailer.

The ordinance bans discrimination based on a series of classes - including sex, race, color, ethnicity, national origin, age, religion, disability, pregnancy and genetic information, as well as family, marital or military status - but opponents have focused on its protection of sexual orientation and gender identity.